Electrical discharge tube circuits



May 19, 1936. L. F. B. CARINI ELECTRICAL DISCHARGE TUBE CIRCUITS 2 Sheets-Sheet 1 Filed Nov. 14, 1934 r I1r:... .1-

INVENTOR.

May 19, 1936.,

L. F. B. CARINI ELECTRICAL DISCHARGE TUBE CIRCUITS Filed Nov. 14 1934 2 Sheets-Sheet 2 INVEN TOR.

KM TTO Eva.

Patented Bray 3%, 1%36 UNITED STATES- PATENT OFFICE ELECTRICAL DISCHARGE TUBE CIRCUITS Louis r. B. Carini, Wethersfield, Conn.

Application November 14, 1934, Serial No. 753,036 12 Claims. (Cl. 250-36) This invention relates to electrical apparatus generally. More particularly, this invention relates to electrical discharge tube circuit arrangements particularly adapted for use as relays and controls.'

An object of this invention is to provide a compact, sensitive and efficient electron discharge device oscillation generator adapted to be readily adjusted to maximum sensitivity and stability for the production of oscillations in accordance with a predetermined condition.

Another object of this invention is to provide a compact, sensitive and efficient electron discharge device or thermionic tube circuit arrangement adapted to operate as a relay controllable by a predetermined unbalancing of the circuit thereof to generate oscillations for operating a relay circuit.

Still another object ofv this invention is to provide a balanced circuit arrangement employing a dual type electron discharge .device or thervmionic tube for the purpose of generating and amplifying electrical oscillations during the predetermined, unbalancing of the balanced circuit.

A further object of this invention is to pro-- vide a balanced bridge circuit connected between a pair of electron discharge devices or thermionic tubes one of which is adjusted to generate a oscillations and the other of which is adjusted to amplify the oscillations.

In accordance with this invention I provide a sensitive and reliable circuit controlling arrangement which may be employed in numerous ways to control alarms, detecting circuits, mechanical production apparatus and conveyors and similar arrangements.

The apparatus of my invention consists of a sensitive balanced oscillation generating circuit adapted to produce oscillations upon the setting up of the predetermined electrical conditions. Oscillations of any predetermined frequency may be generated by the generator once the predetermined electrical conditions are set up. These oscillations'are impressed upon the circuit of an amplifying device, preferably an electron discharge device, and the amplitude thereof is increased and if necessary rectified to operate a suitable electromagnetic relay. A source of direct current supply for energizing the anode circuits of the oscillation generator and amplifier is incorporated therewith whereby the whole unit may be conveniently portable and set up for immediate use;

Further details of the circuit arrangement and details of my invention will be apparent from the following drawings in which Figures 1 and 2 illustrate the circuit arrangements of my invention and Figures 3, 4, 5 and 6 illustrate forms of control adapted for use with the circuit.

Referring to the drawings in detail reference numeral I" designates an electron discharge de vice of the dual type employing a cathode 2, cathode heating filament ,3, grid electrodes 6 and 5 and anodes 6 and l. I

A variable grid biasing'resistor 8 is connected to the grid 4 and the cathode 2 and alsoto the condensers I2 and It. A choke coil I3 is connected across the condenser I2 and to the voltage reducing resistor I! which is connected in series with the filaments 3 and 30 to enable these filaments to be heated from a relatively high voltage supply, such as, a 110 volt lighting circuit.

A resistor 9 and condenser I comprising a parallel circuit, are connected between the grid 5 and the filament circuit of this tube I, as illustrated in Fig. 1. The anodes 6 and 'I of the tube 5 are connected across one inductance leg I8 of the inductance and capacity bridge circuit, which includes the capacity II, inductance I8, capacity I9 and inductance connected into a ring, to form the legs of the bridge circuit, such as, a Wheatstone'bridge, and capacity 2i connected across two legs of the bridge.

The inductances I8 and 20 and capacities I1 and I9 are connected together into a ring desig nated by the letters B, C, D and E, as illustrated. The condenser I9 is connected to the points C and D of said ring, forming terminals of the inductances I8 and 20, respectively, and the condenser I1 is connected to the points B and E of said ring, forming the other terminals of the inductances I8 and 20, respectively. The condenser 2I is connected across the points C and E of said ring. The anodes 6 and I of the tube I are connected to the points B and C, respectively and the grid electrodes 4 and 5 are connected to the pointsE and D, respectively. Stabilizing condenser 2I is connected to the points E and C.

The condensers I5 and I4 are connected to the bridge circuit and the cathode 2 of the tube I, respectively and to the terminals A and G, which are the input control terminals, as willbe hereinafter more fully explained.

- A small current meter 22 preferably a milliammeter is connected to the bridge circuit at a point where the capacities I9 and 2| and the inductance I8 are connected together. This meter is connected to the electrical winding of the relay 23 which is connected to the fuse 24 and the filter circuit of the power supply. This filter includes the condenser 26 and the choke coil 21. Tube 29, having a filament 30, cathode 3| and plate 32, is used for rectifying the H0 volt alternating current supply. Where a direct current supply is available the rectifier tube 29 and filter may be dispensed with, if desired. This tube may, of course, be of any of the conventional designs, including the mercury vapor, gas filled or vacuum type of rectifiers. Contact types of rectifiers employing dissimilar metal surfaces having substantially unilateral electrical conducting properties may also be employed in place of the tube 29.

A resistor 28 is shunted across the filament 30 for the purpose of by-passing some of the heating current required by the filaments 3 of tube l, where these latter filaments require a greater heating current than the filament 30. It is, of course, understood that a resistor may be shunted across the filament 3 in cases where the rectifier tube filament requires a greater heating current. In cases where dissimilar metal or chemical contact type rectifiers are used in place of the tube 29, the size of the resistor 28 would be reduced to compensate for the resistance of the filament 30 and, of course, the unit 28 could then be made a part of the resistor ll.

The relay 23 controls the armature 33 to close the circuits of the contact 34 or contact 35. A suitable fuse 31 is included in the circuit controlled by the relay. A condenser 38 and resistance 36 are connected to the external electrical circuit controlled by the relay, where desired and it is, of course obvious that the arrangement of these units in the electrical circuit is governed to a large extent by the type of circuit.

The characteristics and values of the circuit components connected to the electrodes of .the tube l are chosen and adjusted to permit one section of this dual tube to generate electrical oscillations and the other section to amplify or increase the amplitude of these oscillations.

The values of the various circuit components found to give satisfactory results with the dual type tube are as follows: Condensers l0, l2, l4, l5, l1, l9, 2|, 25, 2E and 38 are preferably, 0.004 to 0.006 microfarad, 0.1 to 0.3 microfarad, 0.1 to 1 microfarad, minimum one micro-microfarad, 1 to 80 micro-microfarads, 0.005 microfarad, 1 to 75 micro-microfarads, 0.25 to 2 microfarads, 4 to 8 microfarads and 1 to 4 microfarads, respectively.

The resistors 8 and 9 are preferably variable between wide limits and resistor 9 may be varied between very low values to several million ohms. Resistor 9 may be anywhere from one to five megohms. Resistors II and 28 are 165 and 25 ohms, respectively. Choke coil I3 is 20 microhenries inductance and 50 to 100 ohms direct thereof current resistance. The choke 21 is a conventionalfilter choke such as is used in power supplies and is about 15 henries inductance.

In the circuit illustrated in Figure 1 the anode 6 co-operates with the grid 4 and the cathode 2 in the generation of oscillations whereas the section of the tube including anode 1, grid 5 and cathode 2 function, together with the interconnecting components as an amplifier.

For the purpose of controlling the generation of oscillations by the first or oscillator section of the tube I, difierent arrangements illustrated in Figs. 3, 4, 5 and 6, may be used.

A conducting plate 39 is connected to the ter minal A, as illustrated in Fig. 3. This conducting plate may be held upon a convenient surface, such as, a show window glass 4| by means of rubber vacuum cups 40 or similar support The plate 39,

in this arrangement functions as one plate of a condenser, the other plate, co-operating with the circuit of the terminal G may be connected to this latter terminal and positioned at a short distance from the plate 39 or the ground GND connected 5 to the cathode circuit of tube l as shown in Fig. 1, may be used without an additional plate connected to the terminal G.

The purpose of the plates connected to the terminals A and G and the ground connection is to permit the control of the operation of the oscillation generator by the variation of the electrical capacity formed by these conducting plates or by the capacity formed by the plate connected to terminal A and the ground. This variation in capacity may be obtained by the presence or absence of a human being adjacent to the plate or plates or by the waving of the operators hand adjacent thereto.

Other forms of circuit control adapted to be used with the electron discharge device circuit herein described, are illustrated in Figs. 4, 5 and 6. A mercury type switch 42, shown in Fig. 4.

having electrodes 43 and. 44, connected to the terminals A and G, respectively, is suitable for 25 controlling the circuit between the terminals A and G, and when attached to a bi-metallic strip 46 by means of a suitable clamp 41, this switch may be employed to control the operation of the oscillation generator at a predeter-- 30 mined temperature. The bi-metal strip 48 is preferably wound into a spiral with the inner end attached, by a suitable member a to a panel or wall. The outer end of the spiral bimetal strip is attached to the switch clamp 41, 35 of suitable material.

Fig. 5 illustrates a modified form of control en1- ploying a bi-metallic strip 48 or similar teinperature responsive expansible member. A contact supporting member 48 is attached to the free end of the spiral 46. One of the contacts 49 is supported by the member 48 and the other is adjusiably supported by a suitable screw and bracket 49a. Likewise, the contacts 50 are supported, one by the member 48 and the other by the screw and bracket 50a, which is adjust- The contacts 49 are connected to the terminals A and G of the electron discharge device apparatus to control the generation of oscillations and if desired the auxiliary contacts 50 u may be used to control the energization of the electron discharge device apparatus itself, from the 110 volt circuit. In this way the apparatus need not be energized from the 110 volt circuit except during the intervals determined by temperature.

As illustrated in Fig. 6 a photo-electric cell 5| or other type of light sensitive device may be used to control the circuit of the oscillation generating apparatus.

The dual electron discharge device I illustrated in Fig. 1 may be replaced by two electron discharge devices la and lb. The device laincludes cathode 2a, heater 3a, grid 4 and anode 6 and the device lb includes cathode 2b, heater 3b, grid 5 and anode I. In case two tubes la and lb are used the small condenser lc, which corresponds to the inter-electrode capacity lc of Fig. 1 is connected between the anodes 6 and I of Fig. 2.

The operation of the apparatus shown in Figs.

1 and 2 is substantially the same. The variable circuit components are adjusted in such a way that the oscillation generator, including the anode 6, grid and cathode 2, does not generate oscil lations except when the circuit between the terminals A and G is properly adjusted or closed. It is, of course, obvious that any one or more of many forms of control may be used in conjunction with this circuit and that the condensers l4 and I5 may be removed or adjusted to compensate for the different forms of control.

In practice it has also been found that the small choke coil it, connected across the con. denser l2, must be of a certain size in order that propersensitivity for the production of oscillations be obtained.

The circuit of the oscillation generator section of the electron discharge device i is adjusted by properly proportioning the circuit components including the choke coil I3, variable condensers l5, l7 and 2i and the resistor 8 so that a certain variation in the electrical capacity of the plates connected to the terminals A and G, causes the discharge device to generate electrical oscillations.

The electrical oscillations produced by the generator section of the tube i are amplified by the second section, including the electrodes 2, 5 and i and the electro-magnetic relay 23, which is connected to the anode l of tube l and is matched in impedance characteristics to operate efficiently in conjunction with the amplifier tube section, is controlled in accordance with the oscillations produced and amplified by the tube.

The oscillation generator section of the tube i operates to generate oscillations only during the period in which the capacity of the plates connected between the terminals is changed by the presence of a foreign body. It is, of course, possible that the tube could be controlled to stop generating oscillations when the foreign body is adjacent to the plate or plates, rather than start the generation of oscillations and such results may be obtained by proper circuit adjustment whereby the tube circuit is in an oscillatory state at all times except when the foreign body is in a predetermined location with respect thereto.

It is also desirable to shield the diiferent parts of the apparatus properly, where uns'tability of operation to a marked degree is encountered, as is likely if high frequency oscillations are produced.

From the foregoing it is apparent that I have described this invention in detail. However, I do not desire to limit this invention to the exact details set forth except in so far as they are defined by the following claims. 1

What I claim and desire to secure by Letters Patent of the United States is as follows:

1. In electrical discharge apparatus the combination of a dual electron discharge device having a cathode, a pair of grid electrodes and a pair of anodes, a balanced circuit, comprising a ring including a plurality of legs, inductance and capacity elements connected in said legs, one of the legs of said circuit being connected between said anodes and another of the legs of said circuit being connected between said grid electrodes, means forimpressing a certain potential bias upon each of said grid electrodes, means for energizing the circuits of said anodes and means for.

causing one section of. said dual discharge device, including said cathode, one of said grid electrodes and one of said anodes to generate electrical oscillations and means for causing the other section of said dual tube, including said cathode, the other of said grid electrodes and the other of said nected between the other of said grid electrodes and the corresponding anode of said discharge device, another of said legs being connected between said grid electrodes and another of said legs being connected between said anodes, means for impressing biasing potentials upon said grid electrodes with respect to said cathode and means for causing said electron discharge device to produce and amplify electrical oscillations.

3. In electrical discharge tube apparatus the combination of a pair of electron discharge devices each having a cathode, a grid electrode and an anode, a Wheatstone bridge circuit having a plurality of legs including inductance and capacity elements, connections between the grid electrodes and anodes of said electron discharge devices and the legs of said bridge circuit,- means for impress ing biasingpotentials on said grid electrodes and means including a variable impedance element connected across two legs of said bridge for causing one of said electron discharge devices to gen erate electrical oscillations and means for causing the other of said electron discharge devices to amplify said oscillations.

4. In electrical discharge tube apparatus the combination of a pair of electron discharge devices each having a cathode, a grid electrode and an anode, a Wheatstone bridge circuit having a plurality of legs including inductance and capacity elements, connections between the grid electrodes and anodes of said discharge devices and the legs of said bridge circuit, means for connecting a predetermined capacity to the grid and cathode of one of said discharge devices, means including a variable impedance element. connected across two legs of said bridge for causing said last-mentioned discharge device to generate oscillations, means for impressing an anode poten tial on the anode of said last-mentioned discharge device, and means for causing the other of said devices to amplify said oscillations.

combination of an oscillation generator having input and output electrodes an amplifier having input and output electrodes, a Wheatstone bridge circuit including a plurality of inductance and capacity units connected to form the legs thereof, one of the legs of said bridge circuit being connected between the output and input electrodes of said oscillation generator, another leg of said bridge circuit being connected between said input and output electrodes of said amplifier, means for balancing said bridge circuit to prevent said oscillation generator from generating oscillations, means to unbalance said bridge circuit to permit said oscillation generator to generate oscillations and means for causing said amplifier to amplify said oscillations.

6. Electrical discharge tube apparatus comprising in combination electrical discharge apparatus having at least two discharge paths each including a cathode, a control electrode and an anode, a source of current supply for energizing said electrical discharge apparatus, a Wheatstone bridge circuit including a pair 01' inductance units and a pair of condensers connected alternately into said bridge circuit, connections for connecting said inductance units between the control electrodes of said two discharge paths and between the anodes of said two discharge paths, connections for coupling the control electrode to the anode of one of said discharge paths through one of said pair of condensers, connections for coupling the control electrode of the other of said discharge paths to the corresponding anode through the other of said pair of condensers, means for altering the external electrical characteristics of at least one of said discharge paths for generating oscillations therein, said oscillations being transferred to the other of said discharge paths through said bridge circuit and circuit control means connected to electrodes of said last mentioned discharge path.

7. An electric discharge device relay comprising a pair of electric discharge devices each having input and output electrodes. a Wheatstone bridge circuit including a plurality of legs, inductance and capacity elements connected in said legs, connections between said Wheatstone bridge and the input and output electrodes of said electric discharge devices, variable impedance means connected to the input electrodes of one of said discharge devices for controllingelectric oscillations generated thereby, connections for impressing said oscillations on the input of the other of said discharge devices through selected legs of said bridge, and indicator means connected to the output circuit of said last mentioned discharge device.

8. In electrical discharge apparatus the combination of a dual electron discharge device having a cathode, a pair of grid electrodes and a pair of anodes, a balanced circuit, comprising a ring including a plurality of legs, a plurality of inductance and capacity elements connected in alternate ones of said legs, one of said legs including one of said inductance elements being connected between said anodes and another of said legs including another of said inductance elements being connected between said grid elec trodes, means for impressing a certain potential bias upon each of said grid electrodes, means for energizing the circuits of said anodes and means for causing one section of said dual discharge device, including said cathode, one of said grid electrodes and one of said anodes to generate electrical oscillations and means for causing the other section of said dual tube, including said cathode,

the other of said grid electrodes and the other of said anodes to amplify the oscillations generated by said first section of said discharge device.

9. In electrical discharge tube apparatus the combination of a dual electron discharge device hav'ng a cathode, a pair of grid electrodes and a pair of anodes, a Wheatstone bridge circuit having a plurality of legs, a plurality of inductance and capacity elements connected in said bridge legs, one of said legs including one of said capacity elements being connected between one of said grid electrodes and the corresponding anode of said discharge device, another of said legs ineluding another of said capacity elements, said last mentioned leg being connected between the other or said grid electrodes and the correspond ing anode, and another of said legs being connected between said anodes, means for impressing biasing potentials upon said grid electrodes with respect to said cathode and means for causing said electron discharge device to produce and amplify electrical oscillations.

10. In eelctrical discharge tube apparatus the combination of a pair of electron discharge devices each having a cathode, a grid electrode and an anode, a Wheatstone bridge circuit having a plurality of legs including inductance and capacity elements, a condenser connected across two of the legs of said bridge, connections for con necting the grid electrodes and anodes of said electron discharge devices across selected legs of said bridge circuit, for intercoupling said grid electrodes and anodes, means for impressing biasing potentials on said grid electrodes and means for causing one of said electron discharge devices to generate electrical oscillations and the other of said electron discharge devices to amplify said oscillations,

11. In electrical discharge tube apparatus the combination of a pair of electron discharge devices each having a cathode, a grid electrode and an anode, a Wheatstone bridge circuit having a plurality of legs including inductance and capacity elements, connections for connecting the grid electrodes and anodes of said discharge devices across selected legs of said bridge circuit, for intercoupling said grid electrodes and anodes, means ior connecting a predetermined capacity between the grid and cathode of one of said discharge devices, means for impressing an anode potential on the anode of said last-mentioned discharge device through one of the inductance elements of said bridge for enabling said discharge device to generate oscillations, connections for impressing the oscillations from said oscillation generating discharge device on the other of said discharge devices, and means for impressing grid biasing potentials on said discharge devices.

12. In electrical discharge tube apparatus the combination of an oscillation generatorhaving an input and an output electrode, an amplifier having an input and an output electrode, a Wheatstone bridge circuit including a plurality of inductance'and capacity units connected to form the legs thereof, one of the legs of said bridge circuit being connected between the input and output electrodes of said oscillation generator, 2. Second leg of said bridge circuit being connected between said input and output electrodes of said amplifier, a third leg of said bridge circuit being connected between an input electrode of said oscillation generator and an input electrode of said amplifier, a fourth leg of said bridge circuit being connected between an output electrode of said oscillation generator and an output electrode of said amplifier, means for energizing the circuits of said oscillation generator and said ampliher and means for controlling the generation of oscillations by said oscillation generator.

LOUIS F. B. CARINI. 

